Effects of LNAPLs Contamination on the Basic Properties of Silty Clay

Soil contamination is a worldwide problem nowadays. Basic properties of soil will be changed after contaminated. Diesel oil and kerosene are typical light non-aqueous phase liquids (LNAPLs), Atterberg Limits, pH, particle size distribution will be changed after contaminated by these oils. In this study, 0# diesel oil (in Chinese standard) and kerosene were used as contaminations, classical Yangtze River back swamp silty clay in Nanjing City was used as the study material, contaminated soils with different oil contents of 0%, 2%, 4%, 6%, 8%, and 10% (ratio of oil weight to soil dry weight) were artificial mixed in the laboratory. Laboratory tests including soil grain size distribution, pH, Atterberg limits were conducted to verify the effect of oils on soil properties. Scanning electron microscope were also done to examine the change of microstructure of soils before and after contaminated. Rules of contaminations effects on the change of soil basic properties were obtained. Results show that different oil contaminated soils have similar change rules. With the increase of oil content, both of clay particle and silt particle increase. Micrograph of scanning electron microscope show that soil small particles increase with the increase of oil content. Both of the two contaminated soil pH, liquid limit, plastic limit and plasticity index decrease all decrease with the increase of oil content.